Resoudre des équations: a-15=-5 -5b=27 4c+5=2c-20 2 (3d-4)=7 (2d-3)+12 urgent stp☺

Bonjour,

Résoudre des équations:

a-15=-5

a - 15 + 15 = -5 + 15

• a = 10

-5b=27

-5b/-5 = 27/-5

• b = -27/5

4c+5=2c-20

4c + 5 - 5 = 2c - 20 - 5

4c - 2c = 2c - 25 - 2c

2c = -25

2c/2 = -25/2

• c = -25/2

2(3d-4)=7(2d-3)+12

6d - 8 = 14d - 21 + 12

6d - 8 - 6d = 14d - 9 - 6d

-8 + 9 = 8d

1 = 8d

8d/8 = 1/8

• d = 1/8

a -15 = -5 === a = +15 -5 ===== a = 10 -5b = 27 ===== b = 27/-5 4c +5 =2c -20 === 4c -2c = -5 -20 === 2c = -25 ==== c = -25/2

2(3d-4)=7(2d-3)+12

6d -8 = 14d -21 +12 6d -14d = +8 -21 +12

-8d = -1 d = -1/-8 = +1/8